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A kind of preparation method of multistage spherical sodium vanadium phosphate composite cathode material

A composite positive electrode material, sodium vanadium phosphate technology, applied in the direction of battery electrodes, structural parts, electrical components, etc., can solve the problems of poor material performance, easy uneven thickness of carbon coating, cumbersome steps, etc., to reduce the difficulty of preparation and cost, improved electrochemical performance, and the effect of complete grain development

Inactive Publication Date: 2020-11-24
WUHAN UNIV OF TECH
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Problems solved by technology

However, there are still many problems in this method. The carbon coating is easy to be uneven, the thickness is not easy to control, and the material performance is not good.
The publication number is CN106898752A, which discloses a method for preparing a porous spherical sodium vanadium phosphate / carbon tube composite positive electrode material, but the carbon nanotubes used in this method are not easy to synthesize, and the cycle stability needs to be further improved
The publication number is CN107845796A, which discloses a carbon-doped sodium vanadium phosphate positive electrode material and its preparation method. The precursor is obtained by sol-gel combined with high-temperature calcination, and then a buffer solution is prepared, mixed and dispersed with dopamine hydrochloride, and then solid-liquid separation, Drying; finally, the positive electrode material is obtained through two stages of calcination; but the method is complicated, the performance of the synthesized material is not good under high magnification, and the industrialization prospect is not good
The publication number is CN107611367A, which discloses a porous spherical carbon-coated sodium vanadium phosphate composite positive electrode material and its preparation method. The method needs to add an organic solvent with a higher polarity than water for hydrothermal treatment, which increases the reaction cost and requires centrifugation and washing precipitation. cumbersome steps
Publication No. CN105244503A discloses a preparation method of a graded graphene-modified spherical sodium ion electrode material. The method adopts spray drying and high-temperature treatment to obtain a graded graphene-modified spherical material, but the method has a complex spheroidizing mechanism, The cost is high and the cycle performance needs to be further improved

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  • A kind of preparation method of multistage spherical sodium vanadium phosphate composite cathode material
  • A kind of preparation method of multistage spherical sodium vanadium phosphate composite cathode material
  • A kind of preparation method of multistage spherical sodium vanadium phosphate composite cathode material

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Embodiment 1

[0033] A preparation method of a multi-stage spherical sodium vanadium phosphate composite positive electrode material, the specific steps are as follows:

[0034] (1) Weigh 2.941 g of trisodium citrate dihydrate and 1.5015 g of urea, dissolve them in 40 ml of deionized water, stir in a water bath at 60°C, and fully dissolve to obtain a colorless solution A;

[0035](2) Weigh 2.3398g of ammonium metavanadate, 3.4509g of ammonium dihydrogen phosphate and 2.7009g of anhydrous oxalic acid and dissolve them in 40ml of deionized water, stir in a water bath at 60°C, and fully dissolve to obtain blue solution B;

[0036] (3) Add solution B slowly to solution A drop by drop, and stir in a water bath at 60°C for 30 minutes to form a mixed solution;

[0037] (4) Put the mixed solution obtained in step (3) into a hydrothermal kettle, conduct a hydrothermal reaction at 160° C. for 12 hours, dry and grind to obtain a precursor powder;

[0038] (5) Under the protection of nitrogen, heat th...

Embodiment 2

[0044] A preparation method of a multi-stage spherical sodium vanadium phosphate composite positive electrode material, the specific steps are as follows:

[0045] (1) Weigh 2.941 g of trisodium citrate dihydrate and 0.75075 g of urea and dissolve them in 40 ml of deionized water, stir in a water bath at 50°C, and fully dissolve to obtain a colorless solution A;

[0046] (2) Weigh 2.3398g of ammonium metavanadate, 3.4509g of ammonium dihydrogen phosphate and 2.7009g of anhydrous oxalic acid and dissolve them in 40ml of deionized water, stir in a water bath at 50°C, and fully dissolve to obtain blue solution B;

[0047] (3) Add solution B slowly to solution A drop by drop, and stir in a water bath at 50°C for 15 minutes to form a mixed solution;

[0048] (4) Put the mixed solution into a hydrothermal kettle, conduct a hydrothermal reaction at 140°C for 6 hours, dry and grind to obtain the precursor powder;

[0049] (5) Heat the precursor powder at 300°C for 4 hours under the p...

Embodiment 3

[0052] A preparation method of a multi-stage spherical sodium vanadium phosphate composite positive electrode material, the specific steps are as follows:

[0053] (1) Weigh 2.941 g of trisodium citrate dihydrate and 3.003 g of urea and dissolve them in 40 ml of deionized water, stir in a water bath at 80°C, and fully dissolve to obtain a colorless solution A;

[0054] (2) Weigh 2.3398g of ammonium metavanadate, 3.4509g of ammonium dihydrogen phosphate and 2.7009g of anhydrous oxalic acid and dissolve them in 40ml of deionized water, stir in a water bath at 80°C, and fully dissolve to obtain blue solution B;

[0055] (3) Add solution B slowly to solution A drop by drop, and stir in a water bath at 80°C for 45 minutes to form a mixed solution;

[0056] (4) Put the mixed solution into a hydrothermal kettle, conduct a hydrothermal reaction at 180°C for 18 hours, dry and grind to obtain a precursor powder;

[0057] (5) Heat the precursor powder at 400°C for 6 hours under the prot...

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Abstract

The invention relates to a method for preparing a multi-stage spherical sodium vanadium phosphate composite positive electrode material. The method comprises the following steps: using oxalic acid, avanadium source, a sodium source and a phosphorus source as main raw materials, and using urea as a pelletizing agent and a carbon source, forming a spherical sodium vanadium phosphate precursor by ahydrothermal method, drying the precursor and subjecting to two-step heat treatment in a nitrogen atmosphere to obtain the multi-stage spherical sodium vanadium phosphate composite positive electrodematerial. The sodium vanadium phosphate composite positive electrode material obtained by the invention has multi-stage spherical morphology, and the microsphere particles have a diameter of 1 to 5 mum. The positive electrode material can be used for a sodium ion battery. In a working voltage range of 2.5 V to 4.3 V, under the 0.1C rate, the first-round discharge specific capacity can reach 116.47 mAh / g; under the 10C rate, the first-round discharge specific capacity is 95 mAh / g, and the capacity retention rate is 98% or above after 100 times of complete charging and discharging process withcertain current. Compared with the prior art, the method not only improves the electrochemical performance of the positive electrode material, but also the method for synthesizing the spherical morphology is simple and effective.

Description

technical field [0001] The invention relates to a preparation method of a multi-stage spherical sodium vanadium phosphate composite positive electrode material, belonging to the technical field of sodium ion battery positive electrode materials. Background technique [0002] At present, compared with lithium-ion batteries, sodium-ion batteries have multiple advantages such as abundant element sources, uniform geographical distribution, and significantly lower costs, so they are considered to be an important substitute for lithium-ion batteries. In addition, sodium ions and lithium ions belong to the main group I elements of the periodic table of elements, and have similar outer nuclear electron shell structures, while sodium ions have larger radii and heavier masses. The increased ionic radius has two decisive advantages: one It is the small polarization caused by the large radius of sodium ions, which makes the solubility of sodium ions in the electrolyte small, thereby red...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/054
CPCH01M4/366H01M4/5825H01M4/625H01M4/628H01M10/054Y02E60/10
Inventor 陶海征刘金梅王朝阳
Owner WUHAN UNIV OF TECH
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